cregit-Linux how code gets into the kernel

Release 4.8 lib/debugobjects.c

Directory: lib
/*
 * Generic infrastructure for lifetime debugging of objects.
 *
 * Started by Thomas Gleixner
 *
 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
 *
 * For licencing details see kernel-base/COPYING
 */


#define pr_fmt(fmt) "ODEBUG: " fmt

#include <linux/debugobjects.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/hash.h>


#define ODEBUG_HASH_BITS	14

#define ODEBUG_HASH_SIZE	(1 << ODEBUG_HASH_BITS)


#define ODEBUG_POOL_SIZE	1024

#define ODEBUG_POOL_MIN_LEVEL	256


#define ODEBUG_CHUNK_SHIFT	PAGE_SHIFT

#define ODEBUG_CHUNK_SIZE	(1 << ODEBUG_CHUNK_SHIFT)

#define ODEBUG_CHUNK_MASK	(~(ODEBUG_CHUNK_SIZE - 1))


struct debug_bucket {
	
struct hlist_head	list;
	
raw_spinlock_t		lock;
};


static struct debug_bucket	obj_hash[ODEBUG_HASH_SIZE];


static struct debug_obj		obj_static_pool[ODEBUG_POOL_SIZE] __initdata;

static DEFINE_RAW_SPINLOCK(pool_lock);

static HLIST_HEAD(obj_pool);


static int			obj_pool_min_free = ODEBUG_POOL_SIZE;

static int			obj_pool_free = ODEBUG_POOL_SIZE;

static int			obj_pool_used;

static int			obj_pool_max_used;

static struct kmem_cache	*obj_cache;


static int			debug_objects_maxchain __read_mostly;

static int			debug_objects_fixups __read_mostly;

static int			debug_objects_warnings __read_mostly;

static int			debug_objects_enabled __read_mostly
				= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;


static struct debug_obj_descr	*descr_test  __read_mostly;

static void free_obj_work(struct work_struct *work);
static DECLARE_WORK(debug_obj_work, free_obj_work);


static int __init enable_object_debug(char *str) { debug_objects_enabled = 1; return 0; }

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thomas gleixnerthomas gleixner18100.00%1100.00%
Total18100.00%1100.00%


static int __init disable_object_debug(char *str) { debug_objects_enabled = 0; return 0; }

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kyle mcmartinkyle mcmartin18100.00%1100.00%
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early_param("debug_objects", enable_object_debug); early_param("no_debug_objects", disable_object_debug); static const char *obj_states[ODEBUG_STATE_MAX] = { [ODEBUG_STATE_NONE] = "none", [ODEBUG_STATE_INIT] = "initialized", [ODEBUG_STATE_INACTIVE] = "inactive", [ODEBUG_STATE_ACTIVE] = "active", [ODEBUG_STATE_DESTROYED] = "destroyed", [ODEBUG_STATE_NOTAVAILABLE] = "not available", };
static void fill_pool(void) { gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN; struct debug_obj *new; unsigned long flags; if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL)) return; if (unlikely(!obj_cache)) return; while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) { new = kmem_cache_zalloc(obj_cache, gfp); if (!new) return; raw_spin_lock_irqsave(&pool_lock, flags); hlist_add_head(&new->node, &obj_pool); obj_pool_free++; raw_spin_unlock_irqrestore(&pool_lock, flags); } }

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thomas gleixnerthomas gleixner8990.82%360.00%
vegard nossumvegard nossum88.16%120.00%
dan carpenterdan carpenter11.02%120.00%
Total98100.00%5100.00%

/* * Lookup an object in the hash bucket. */
static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b) { struct debug_obj *obj; int cnt = 0; hlist_for_each_entry(obj, &b->list, node) { cnt++; if (obj->object == addr) return obj; } if (cnt > debug_objects_maxchain) debug_objects_maxchain = cnt; return NULL; }

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thomas gleixnerthomas gleixner64100.00%1100.00%
Total64100.00%1100.00%

/* * Allocate a new object. If the pool is empty, switch off the debugger. * Must be called with interrupts disabled. */
static struct debug_obj * alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr) { struct debug_obj *obj = NULL; raw_spin_lock(&pool_lock); if (obj_pool.first) { obj = hlist_entry(obj_pool.first, typeof(*obj), node); obj->object = addr; obj->descr = descr; obj->state = ODEBUG_STATE_NONE; obj->astate = 0; hlist_del(&obj->node); hlist_add_head(&obj->node, &b->list); obj_pool_used++; if (obj_pool_used > obj_pool_max_used) obj_pool_max_used = obj_pool_used; obj_pool_free--; if (obj_pool_free < obj_pool_min_free) obj_pool_min_free = obj_pool_free; } raw_spin_unlock(&pool_lock); return obj; }

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thomas gleixnerthomas gleixner13495.71%266.67%
mathieu desnoyersmathieu desnoyers64.29%133.33%
Total140100.00%3100.00%

/* * workqueue function to free objects. */
static void free_obj_work(struct work_struct *work) { struct debug_obj *obj; unsigned long flags; raw_spin_lock_irqsave(&pool_lock, flags); while (obj_pool_free > ODEBUG_POOL_SIZE) { obj = hlist_entry(obj_pool.first, typeof(*obj), node); hlist_del(&obj->node); obj_pool_free--; /* * We release pool_lock across kmem_cache_free() to * avoid contention on pool_lock. */ raw_spin_unlock_irqrestore(&pool_lock, flags); kmem_cache_free(obj_cache, obj); raw_spin_lock_irqsave(&pool_lock, flags); } raw_spin_unlock_irqrestore(&pool_lock, flags); }

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thomas gleixnerthomas gleixner8992.71%375.00%
vegard nossumvegard nossum77.29%125.00%
Total96100.00%4100.00%

/* * Put the object back into the pool and schedule work to free objects * if necessary. */
static void free_object(struct debug_obj *obj) { unsigned long flags; int sched = 0; raw_spin_lock_irqsave(&pool_lock, flags); /* * schedule work when the pool is filled and the cache is * initialized: */ if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache) sched = keventd_up(); hlist_add_head(&obj->node, &obj_pool); obj_pool_free++; obj_pool_used--; raw_spin_unlock_irqrestore(&pool_lock, flags); if (sched) schedule_work(&debug_obj_work); }

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thomas gleixnerthomas gleixner7192.21%360.00%
vegard nossumvegard nossum45.19%120.00%
marcin slusarzmarcin slusarz22.60%120.00%
Total77100.00%5100.00%

/* * We run out of memory. That means we probably have tons of objects * allocated. */
static void debug_objects_oom(void) { struct debug_bucket *db = obj_hash; struct hlist_node *tmp; HLIST_HEAD(freelist); struct debug_obj *obj; unsigned long flags; int i; pr_warn("Out of memory. ODEBUG disabled\n"); for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) { raw_spin_lock_irqsave(&db->lock, flags); hlist_move_list(&db->list, &freelist); raw_spin_unlock_irqrestore(&db->lock, flags); /* Now free them */ hlist_for_each_entry_safe(obj, tmp, &freelist, node) { hlist_del(&obj->node); free_object(obj); } } }

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thomas gleixnerthomas gleixner8875.21%240.00%
vegard nossumvegard nossum2723.08%120.00%
fabian frederickfabian frederick21.71%240.00%
Total117100.00%5100.00%

/* * We use the pfn of the address for the hash. That way we can check * for freed objects simply by checking the affected bucket. */
static struct debug_bucket *get_bucket(unsigned long addr) { unsigned long hash; hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS); return &obj_hash[hash]; }

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thomas gleixnerthomas gleixner36100.00%1100.00%
Total36100.00%1100.00%


static void debug_print_object(struct debug_obj *obj, char *msg) { struct debug_obj_descr *descr = obj->descr; static int limit; if (limit < 5 && descr != descr_test) { void *hint = descr->debug_hint ? descr->debug_hint(obj->object) : NULL; limit++; WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) " "object type: %s hint: %pS\n", msg, obj_states[obj->state], obj->astate, descr->name, hint); } debug_objects_warnings++; }

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thomas gleixnerthomas gleixner5660.22%125.00%
stanislaw gruszkastanislaw gruszka3133.33%125.00%
arjan van de venarjan van de ven33.23%125.00%
mathieu desnoyersmathieu desnoyers33.23%125.00%
Total93100.00%4100.00%

/* * Try to repair the damage, so we have a better chance to get useful * debug output. */
static bool debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state), void * addr, enum debug_obj_state state) { if (fixup && fixup(addr, state)) { debug_objects_fixups++; return true; } return false; }

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thomas gleixnerthomas gleixner3670.59%133.33%
changbin duchangbin du1121.57%133.33%
stephen boydstephen boyd47.84%133.33%
Total51100.00%3100.00%


static void debug_object_is_on_stack(void *addr, int onstack) { int is_on_stack; static int limit; if (limit > 4) return; is_on_stack = object_is_on_stack(addr); if (is_on_stack == onstack) return; limit++; if (is_on_stack) pr_warn("object is on stack, but not annotated\n"); else pr_warn("object is not on stack, but annotated\n"); WARN_ON(1); }

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thomas gleixnerthomas gleixner5789.06%125.00%
fabian frederickfabian frederick46.25%250.00%
fujita tomonorifujita tomonori34.69%125.00%
Total64100.00%4100.00%


static void __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack) { enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; fill_pool(); db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (!obj) { obj = alloc_object(addr, db, descr); if (!obj) { debug_objects_enabled = 0; raw_spin_unlock_irqrestore(&db->lock, flags); debug_objects_oom(); return; } debug_object_is_on_stack(addr, onstack); } switch (obj->state) { case ODEBUG_STATE_NONE: case ODEBUG_STATE_INIT: case ODEBUG_STATE_INACTIVE: obj->state = ODEBUG_STATE_INIT; break; case ODEBUG_STATE_ACTIVE: debug_print_object(obj, "init"); state = obj->state; raw_spin_unlock_irqrestore(&db->lock, flags); debug_object_fixup(descr->fixup_init, addr, state); return; case ODEBUG_STATE_DESTROYED: debug_print_object(obj, "init"); break; default: break; } raw_spin_unlock_irqrestore(&db->lock, flags); }

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thomas gleixnerthomas gleixner20198.53%266.67%
vegard nossumvegard nossum31.47%133.33%
Total204100.00%3100.00%

/** * debug_object_init - debug checks when an object is initialized * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_init(void *addr, struct debug_obj_descr *descr) { if (!debug_objects_enabled) return; __debug_object_init(addr, descr, 0); }

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thomas gleixnerthomas gleixner29100.00%1100.00%
Total29100.00%1100.00%

/** * debug_object_init_on_stack - debug checks when an object on stack is * initialized * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr) { if (!debug_objects_enabled) return; __debug_object_init(addr, descr, 1); }

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thomas gleixnerthomas gleixner29100.00%1100.00%
Total29100.00%1100.00%

/** * debug_object_activate - debug checks when an object is activated * @addr: address of the object * @descr: pointer to an object specific debug description structure * Returns 0 for success, -EINVAL for check failed. */
int debug_object_activate(void *addr, struct debug_obj_descr *descr) { enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; int ret; struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr }; if (!debug_objects_enabled) return 0; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (obj) { switch (obj->state) { case ODEBUG_STATE_INIT: case ODEBUG_STATE_INACTIVE: obj->state = ODEBUG_STATE_ACTIVE; ret = 0; break; case ODEBUG_STATE_ACTIVE: debug_print_object(obj, "activate"); state = obj->state; raw_spin_unlock_irqrestore(&db->lock, flags); ret = debug_object_fixup(descr->fixup_activate, addr, state); return ret ? 0 : -EINVAL; case ODEBUG_STATE_DESTROYED: debug_print_object(obj, "activate"); ret = -EINVAL; break; default: ret = 0; break; } raw_spin_unlock_irqrestore(&db->lock, flags); return ret; } raw_spin_unlock_irqrestore(&db->lock, flags); /* * We are here when a static object is activated. We * let the type specific code confirm whether this is * true or not. if true, we just make sure that the * static object is tracked in the object tracker. If * not, this must be a bug, so we try to fix it up. */ if (descr->is_static_object && descr->is_static_object(addr)) { /* track this static object */ debug_object_init(addr, descr); debug_object_activate(addr, descr); } else { debug_print_object(&o, "activate"); ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE); return ret ? 0 : -EINVAL; } return 0; }

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thomas gleixnerthomas gleixner17060.07%233.33%
changbin duchangbin du4315.19%233.33%
paul e. mckenneypaul e. mckenney4014.13%116.67%
stephen boydstephen boyd3010.60%116.67%
Total283100.00%6100.00%

/** * debug_object_deactivate - debug checks when an object is deactivated * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_deactivate(void *addr, struct debug_obj_descr *descr) { struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; if (!debug_objects_enabled) return; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (obj) { switch (obj->state) { case ODEBUG_STATE_INIT: case ODEBUG_STATE_INACTIVE: case ODEBUG_STATE_ACTIVE: if (!obj->astate) obj->state = ODEBUG_STATE_INACTIVE; else debug_print_object(obj, "deactivate"); break; case ODEBUG_STATE_DESTROYED: debug_print_object(obj, "deactivate"); break; default: break; } } else { struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr }; debug_print_object(&o, "deactivate"); } raw_spin_unlock_irqrestore(&db->lock, flags); }

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thomas gleixnerthomas gleixner14990.85%266.67%
mathieu desnoyersmathieu desnoyers159.15%133.33%
Total164100.00%3100.00%

/** * debug_object_destroy - debug checks when an object is destroyed * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_destroy(void *addr, struct debug_obj_descr *descr) { enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; if (!debug_objects_enabled) return; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (!obj) goto out_unlock; switch (obj->state) { case ODEBUG_STATE_NONE: case ODEBUG_STATE_INIT: case ODEBUG_STATE_INACTIVE: obj->state = ODEBUG_STATE_DESTROYED; break; case ODEBUG_STATE_ACTIVE: debug_print_object(obj, "destroy"); state = obj->state; raw_spin_unlock_irqrestore(&db->lock, flags); debug_object_fixup(descr->fixup_destroy, addr, state); return; case ODEBUG_STATE_DESTROYED: debug_print_object(obj, "destroy"); break; default: break; } out_unlock: raw_spin_unlock_irqrestore(&db->lock, flags); }

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thomas gleixnerthomas gleixner163100.00%2100.00%
Total163100.00%2100.00%

/** * debug_object_free - debug checks when an object is freed * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_free(void *addr, struct debug_obj_descr *descr) { enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; if (!debug_objects_enabled) return; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (!obj) goto out_unlock; switch (obj->state) { case ODEBUG_STATE_ACTIVE: debug_print_object(obj, "free"); state = obj->state; raw_spin_unlock_irqrestore(&db->lock, flags); debug_object_fixup(descr->fixup_free, addr, state); return; default: hlist_del(&obj->node); raw_spin_unlock_irqrestore(&db->lock, flags); free_object(obj); return; } out_unlock: raw_spin_unlock_irqrestore(&db->lock, flags); }

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thomas gleixnerthomas gleixner14188.68%250.00%
vegard nossumvegard nossum106.29%125.00%
christine chanchristine chan85.03%125.00%
Total159100.00%4100.00%

/** * debug_object_assert_init - debug checks when object should be init-ed * @addr: address of the object * @descr: pointer to an object specific debug description structure */
void debug_object_assert_init(void *addr, struct debug_obj_descr *descr) { struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; if (!debug_objects_enabled) return; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (!obj) { struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr }; raw_spin_unlock_irqrestore(&db->lock, flags); /* * Maybe the object is static, and we let the type specific * code confirm. Track this static object if true, else invoke * fixup. */ if (descr->is_static_object && descr->is_static_object(addr)) { /* Track this static object */ debug_object_init(addr, descr); } else { debug_print_object(&o, "assert_init"); debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE); } return; } raw_spin_unlock_irqrestore(&db->lock, flags); }

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christine chanchristine chan12075.47%133.33%
changbin duchangbin du3119.50%133.33%
thomas gleixnerthomas gleixner85.03%133.33%
Total159100.00%3100.00%

/** * debug_object_active_state - debug checks object usage state machine * @addr: address of the object * @descr: pointer to an object specific debug description structure * @expect: expected state * @next: state to move to if expected state is found */
void debug_object_active_state(void *addr, struct debug_obj_descr *descr, unsigned int expect, unsigned int next) { struct debug_bucket *db; struct debug_obj *obj; unsigned long flags; if (!debug_objects_enabled) return; db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); obj = lookup_object(addr, db); if (obj) { switch (obj->state) { case ODEBUG_STATE_ACTIVE: if (obj->astate == expect) obj->astate = next; else debug_print_object(obj, "active_state"); break; default: debug_print_object(obj, "active_state"); break; } } else { struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr }; debug_print_object(&o, "active_state"); } raw_spin_unlock_irqrestore(&db->lock, flags); }

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mathieu desnoyersmathieu desnoyers163100.00%1100.00%
Total163100.00%1100.00%

#ifdef CONFIG_DEBUG_OBJECTS_FREE
static void __debug_check_no_obj_freed(const void *address, unsigned long size) { unsigned long flags, oaddr, saddr, eaddr, paddr, chunks; struct hlist_node *tmp; HLIST_HEAD(freelist); struct debug_obj_descr *descr; enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; int cnt; saddr = (unsigned long) address; eaddr = saddr + size; paddr = saddr & ODEBUG_CHUNK_MASK; chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1)); chunks >>= ODEBUG_CHUNK_SHIFT; for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) { db = get_bucket(paddr); repeat: cnt = 0; raw_spin_lock_irqsave(&db->lock, flags); hlist_for_each_entry_safe(obj, tmp, &db->list, node) { cnt++; oaddr = (unsigned long) obj->object; if (oaddr < saddr || oaddr >= eaddr) continue; switch (obj->state) { case ODEBUG_STATE_ACTIVE: debug_print_object(obj, "free"); descr = obj->descr; state = obj->state; raw_spin_unlock_irqrestore(&db->lock, flags); debug_object_fixup(descr->fixup_free, (void *) oaddr, state); goto repeat; default: hlist_del(&obj->node); hlist_add_head(&obj->node, &freelist); break; } } raw_spin_unlock_irqrestore(&db->lock, flags); /* Now free them */ hlist_for_each_entry_safe(obj, tmp, &freelist, node) { hlist_del(&obj->node); free_object(obj); } if (cnt > debug_objects_maxchain) debug_objects_maxchain = cnt; } }

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thomas gleixnerthomas gleixner26387.38%266.67%
vegard nossumvegard nossum3812.62%133.33%
Total301100.00%3100.00%


void debug_check_no_obj_freed(const void *address, unsigned long size) { if (debug_objects_enabled) __debug_check_no_obj_freed(address, size); }

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thomas gleixnerthomas gleixner25100.00%1100.00%
Total25100.00%1100.00%

#endif #ifdef CONFIG_DEBUG_FS
static int debug_stats_show(struct seq_file *m, void *v) { seq_printf(m, "max_chain :%d\n", debug_objects_maxchain); seq_printf(m, "warnings :%d\n", debug_objects_warnings); seq_printf(m, "fixups :%d\n", debug_objects_fixups); seq_printf(m, "pool_free :%d\n", obj_pool_free); seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free); seq_printf(m, "pool_used :%d\n", obj_pool_used); seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used); return 0; }

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thomas gleixnerthomas gleixner81100.00%1100.00%
Total81100.00%1100.00%


static int debug_stats_open(struct inode *inode, struct file *filp) { return single_open(filp